<font color="yellow">VoteforNimitz - Even at extreme speeds, impacts do not result in flashes, they result in explosion, but no flashes,This is evident during high velocity gas gun tests, and nasa should have known this, so the wouldn't have to mess with the camera exposure, but, it makes for a covienent excuse for the lack of stars. </font><br /><br />Even if light wouldn't have been emitted at all from the initial impact, they would still have had to take into account the ejecta material reflecting the light of the Sun. So, that is an additional, large amount of light that would have had to be compensated for in a long exposure.<br /><br />Regarding gas-gun tests. How much mass and velocity is involved in these tests? What is the material impacting against? How do you know there is no light emitted from the impact? <br /><br />I'm not saying that every impact has enough energy to bump electrons around. However, if you've got enough kinetic energy to generate enough heat to cause an actual, real, explosion, you've probably got enough energy to bump an electron around and emit a photon.<br /> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>